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Volume IV (1988) - Flora of New Zealand Naturalised Pteridophytes, Gymnosperms, Dicotyledons
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Conyza Less.

CONYZA Less.

Usually annual to perennial herbs, rarely shrubs. Lvs alternate, simple, entire, serrate or pinnatifid. Capitula few to numerous in panicles. Involucral bracts in 2-many rows, imbricate, the outer somewhat herbaceous, the inner mostly chartaceous. Receptacle ± flat; scales 0. Outer florets ♀, filiform or shortly ligulate, numerous, in 2-several rows; ligules white to purple. Inner florets ⚥, tubular, fewer than ♀. Achenes all similar, obovoid to cylindric, compressed, hairy, with 0-2 narrow ribs; pappus of scabrid hairs in 1 row, sometimes with a short outer row.

Key

1
Involucral bracts hairy, especially the outer; inner bracts 4-5.5-(6) mm long
2
Involucral bracts glabrous or with a few hairs on midrib or margin only; inner bracts 3-4 mm long
3
2
Cauline lvs flat; capitula 1.5-2 mm diam. at anthesis; involucral bracts green; achenes 1-1.2-(1.4) mm long
1. *albida
Cauline lvs undulate and sometimes twisted; capitula 2-3 mm diam. at anthesis; involucral bracts green, distinctly tinged purple at apex; achenes 1.5-1.8 mm long
3. *bonariensis
3
Inner involucral bracts narrow-triangular; outer florets filiform or with inconspicuous ligules < 0.5 mm long
2. *bilbaoana
Inner involucral bracts linear; outer florets with evident ligules 0.5-1.5 mm long
4
4
Most involucral bracts with a distinct purple spot at apex; cauline lvs entire, glabrous on lower surface; stems with scattered hispid hairs or almost glabrous
5 *parva
All involucral bracts green; at least some cauline lvs remotely serrate, sparsely to moderately hispid on both surfaces; stems sparsely to moderately hispid
4. *canadensis

c. 50 spp., mainly tropical, extending to temperate America and Africa. Naturalised spp. 5.

The treatment adopted here follows that of Michael, P. W., Proc. 6th Asian- Pacific Weed Science Soc. Conf. 1 : 87-95 (1977), who considered spp. naturalised in the Asian-Pacific region. The 5 spp. naturalised in N.Z. are easily identified from fresh material but some useful characters are obscured by drying. Measurements given for capitula diameters are for fresh material at anthesis.

Fig. 19. Involucral bracts of Conyza. A C. bilbaoana; B C. parva. © All rights reserved. [Image: 4X4A]
Fig. 19. Involucral bracts of Conyza. A C. bilbaoana; B C. parva. © All rights reserved. [Image: 4X4A]
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